The purpose of this research study is to compare the ability of different types of Neisseria gonorrhoeae (the organism responsible for gonorrhea), to cause a clinical infection, (signs or symptoms of urethritis such as discomfort in urination, urethral discharge, etc). We predict that the changes we have identified or engineered in some gonococci will render them less capable of causing infection. This study will greatly enhance our understanding of the biology of gonorrhea, and potentially help us to develop a vaccine against this organism, by pointing towards parts of the bacteria that are critical for infection.